The present invention is directed to an apparatus and method for treating contact lenses. More particularly, the invention is directed to a stand-alone apparatus and method by which contact lenses can be cleaned and hydrated without the application of heat, mechanical agitation or cleaning chemicals to the lenses. In a particularly advantageous form the apparatus is single-use and disposable, and comprises a housing including a pair of closable liquid sealed lens containers within which the lenses are contained and brought into contiguous wetted contact with layers of reactive material during the treatment process.
Contact lenses have come into wide use for correcting a wide range of vision deficiencies or cosmetic use. Typically, such lenses are formed from a thin transparent plastic material shaped and dimensioned to fit over the cornea of the eye. The lenses include a concave interior first optical surface for contact with the eye, and an opposed and optically associated convex exterior second optical surface. The two surfaces together define a corrective lens medically prescribed for a particular eye.
Depending on the plastic material used to construct the lenses, the lenses may be either "hard" or "soft". Hard contact lenses, which are comparatively more rigid, are typically formed from a relatively hydrophobic material such as polymethylmethacrylate (PMMA). Soft contact lenses, which are comparatively more pliant, are typically formed from a relatively hydrophylic polymer such as hydroyethylmethacrylate (HEMA), which has the property of being able to absorb and bind a proportionately large amount of water within the polymer network. Soft contact lenses formed from such hydrophilic polymers, when hydrated, are more comfortable to wear than hard lenses because they better conform to the cornea of the eye and cause less irritation when worn for extended periods. For this reason, the great majority of contact lenses presently being prescribed are of the soft type.
Unfortunately, soft contact lenses while being worn may collect contaminants from the eye and its environment. These contaminants, for example, may include proteins and lipids from the tear fluid of the eye, and foreign substances such as cosmetics, soaps, airborne chemicals, dust and other particulate matter. Unless periodically removed, these contaminants may cause abrasion to the surface of the eye, may impair the visual acuity of the lens, and may serve as a nutrient media for potentially harmful microorganisms.
Furthermore, for wearing comfort it is necessary that soft contact lenses be maintained uniformly wetted at all times. While on the eye, the moisture content of the hydrophilic material of the lenses is maintained by tear fluid. However, when the lenses are removed for an extended period, as for cleaning or while sleeping, the lenses may dry out and become irreversibly damaged unless they are externally hydrated.
Consequently, various apparatus and methods have been developed for cleaning and hydrating soft contact lenses. For example, cleaning apparatus has been provided wherein the lenses are submersed in a variety of liquid cleaning agents, such as surfactants, oxidants, disinfectants, enzymatic cleaners, or abrasives. Other cleaning apparatus has been provided which included mechanically operated or electrically powered components for vibrating, rotating, abrading, scrubbing, heating, agitating, subjecting to ultrasonic energy, or otherwise mechanically manipulating the lenses to enhance the cleaning action of the cleaning agent.
Such prior apparatus and methods have not been entirely satisfactory for various reasons, including lack of cleaning effectiveness with respect to certain of the various contaminants found on the lenses, undesirable complexity, excessive time required for use, and dependence on an external power source.
Furthermore, certain prior lens cleaning apparatus and methods required added post-cleaning lens treatment procedures such as rinsing before the lenses could be returned to the eye. Also, such apparatus and methods did not provide a convenient and effective means by which contaminants dislodged during cleaning could be retained for subsequent disposal. Unless a separate and time-consuming cleaning of the apparatus was performed, the dislodged, and possibly infectious contaminants could come into contact with the fingers of the user, and possibly the previously cleaned lenses.
Certain of the prior apparatus and methods such as those involving the application of heat (as during the boiling of the lenses) or those utilizing harsh chemical cleaning agents, actually exacerbated the contamination problem by denaturing the organic components of the contaminants, leaving an intractable layer of contamination. The accretion of such intractable layers over time resulted in increased irritation and decreased visual acuity, and ultimately in premature replacement of the lenses.
Moreover, those prior cleaning apparatus and methods which involved the removal of contaminants by mechanical means had the potential of scratching or otherwise damaging the surfaces of the lenses. Surface scratches potentially weaken the lenses and provide a site at which deleterious organisms such as bacteria can flourish.
Preferably, during the cleaning process (typically overnight) the lenses are maintained in a wetted condition, ready for use when the cleaning process has been completed. Certain prior apparatus did not provide for such hydration, and it was necessary that the lenses be moved to a separate hydration chamber upon completion of the cleaning process. This was not only inconvenient and time consuming,but increased the risk of damage to the lenses from additional handling.
Thus, a demand exists for an apparatus and method by which contaminated contact lenses can be conveniently and effectively cleaned with minimum handling and without the application of exterior power.
Accordingly, it is a general object of the present invention to provide a new and improved system, apparatus and method for cleaning contaminated contact lenses.
It is a more specific object of the invention to provide an apparatus for cleaning contaminated contact lenses wherein the lenses are concurrently maintained in a hydrated state and cleaned.
It is a further object of the present invention to provide a disposable single-use apparatus for cleaning contaminated contact lenses having closable liquid-sealed container within which the lenses are contained while being cleaned.
It is a further object of the invention to provide a self contained apparatus for cleaning a contaminated contact lenses wherein the optical surfaces of the lenses are received in a wetted environment in contiguous contact with reactive layers which attract contaminants from the lenses without the application of external force.
It is a further object of the invention to provide a method of cleaning contaminated contact lenses wherein the optical surfaces of the lenses are concurrently brought into contiguous contact with reactive surfaces in a liquid environment to cause contaminants to migrate from the lenses to the reactive surfaces,